Impact of different synthesis methods on the dispersing effectiveness of isoprenol ether-based zwitterionic and anionic polycarboxylate (PCE) superplasticizers

A series of zwitterionic (amphoteric) and anionic copolymers containing acrylic acid (AA), α-isoprenyloxy ω-polyethyleneglycol (IPEG) macromonomer and 2-trimethylammonium ethylmethacrylate chloride (TMAEMC) was synthesized using two different synthesis methods: in the first method, all monomers were placed into the reactor and subject to a rapid (~15 min) copolymerization while in the second AA and initiator were dosed into the vessel holding macromonomer and TMAEMC. The resulting polymer-mixtures were characterized via SEC and charge titration. Their dispersing effectiveness in cement was compared with that of PCEs prepared according to a conventional industrial process. It was found that the synthesis method greatly influences properties and performance of PCEs. The simple and fast synthesis method #1 produces highly polydisperse PCEs which are as effective as those from the optimized, carefully controlled industrial production which provides a very uniform PCE copolymer. Incorporation of cationic TMAEMC to achieve zwitterionic character only improves clay tolerance of the superplasticizer. [Display omitted]